Bilateral optic nerve aplasia: A rare isolated central nervous system anomaly

Abstract

Optic nerve (ON) aplasia is a rare developmental anomaly comprising of absence of the ON, ganglion cells and the central retinal vessels. It is usually accompanied by a variety of central nervous system (CNS) malformations. We report an extremely rare case of bilateral true ON aplasia occurring as an isolated CNS anomaly. A 10-month-old female child was detected with bilateral absence of fixation, associated with multiple ocular findings of microcornea, anterior embryotoxon, pupillary corectopia, partial aniridia and lens coloboma. The optic disc locations were visible as avascular whitish areas. There were no retinal vessels seen in the disc area or elsewhere. There were bilateral multiple chorioretinal atrophic patches present. B-scan ultrasonography showed bilateral absence of ONs. Magnetic resonance imaging showed thinned out bilateral ONs with a hypoplastic optic chiasma and optic tract. There were no other CNS anomalies. Flash visually evoked potential was unrecordable.

Optic nerve aplasia: A case series

“…The only reported case has been that of bilateral ONA exclusively associated with microphthalmos. [ 10 ]…”

A case of occult bilateral optic nerve aplasia with pituitary dysfunction: hidden anomaly missed on ultrasound

“…Other hormonal anomalies associated with SOD include hypogonadism and adrenal insufficiency, which can cause sudden cardiac death 7. Other CNS associations of bilateral ONA include anencephaly, cerebral atrophy, basal encephalocoele, hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle and posterior fossa cysts 3–5. These anomalies were not present in our patient while corpus callosum was formed (figure 2).…”

“…Unilateral aplasia of the optic nerve is often present in malformed eyes, with no abnormality in brain tissue. Associated malformations of the eye include microphthalmos, cataract, retinal dysplasia, coloboma of the iris and ciliary body, iris hypoplasia, malformation of the chamber angle and persistent hyperplastic primary vitreous 1–4. Rarely, malformation of the CNS like hydranencephaly, orbital meningoencephalocele and anencephaly may also be seen along with unilateral ONA 5 6.…”

Optic Nerve: Developmental Anomalies and Common Tumors

“…In the most recent case, flash visually evoked potentials (VEP) was performed to distinguish ON hypoplasia from ON aplasia and VEP was not recordable [47]. The ON is formed of axons of the retinal ganglion cells, which form the ON that is derived embryologically from the inner neuroblastic layer of the optic cup, and failure of development of these cells is rare [48]. When there is accompanying failure of development of mesodermal elements as well, it is termed aplasia of the ON, which is defined as an absence of optic nerve, ganglion cells, and central retinal vessels [28,49].…”